Major ocean drilling contractors have been put under the cosh by the falling oil price, which has reduced demand for their rigs from oil giants such as Shell and BP – who are also squeezing their exploration costs.

Two leading offshore contract drilling firms – Transocean, which is the world’s largest offshore drilling operator, and Noble Corp – have both recently had their credit ratings downgraded by some financial analysts.

And cost cutting pressures imposed on their clients raise concerns over the increasing likelihood of future problems.

Future offshore accident risk increases amid cost-cutting

In a response to an email from Energydesk, Professor Bea – who worked for Shell in the 1960s and 70s and has worked as a consultant for BP – agreed that cost cutting by rig contractors and their clients could increase the risk of environmental and safety problems in the future – even another environmental disaster like Deepwater Horizon.

He explained that “one of the ‘root causes’ of the Deepwater Horizon disaster were the “Every Dollar Counts” incentives” that BP management put in place two years before the disaster – these included incentives for following safety procedures.

“Experience has demonstrated that ‘cost cutting’ can result in undesirable reductions in the protections that are needed to be ‘safe’,” Bea said.

He added: “In general, the companies do not have a valid and validated way to quantify ‘safe’… it is ‘up to the operator’ to determine what is ‘safe’.

“It is analogous to driving a car without a speedometer and being told and required to ‘drive safely’.”

Therefore, he said that when cost cutting is required, these companies are “not able to determine how the reductions in costs and investments are impacting ‘safety.’”

Downgraded to ‘junk’ and ‘sell’

Oil majors have had to focus on short term cash-flow over exploration programmes as a result of the low oil price.

Shell recently told investors that to “preserve Shell’s financial flexibility” there were opportunities to cut costs, including in their supply chain. This could put additional stress on Noble Corp, in particular, whose main client is Shell, followed by Brazil’s Petrobras.

Eight of Transocean’s 29 ultra-deepwater rigs are currently idle, according to the FT. Even more of the firm’s rigs are at a high risk of being idled, stacked or retired, according to an analysis by UBS.

Transocean’s 2014 Q4 (October to December) results from the end of February revealed a slight fall in revenue. But profits were also down from $233 million in the fourth quarter of the previous year to a loss of $739 million in 2014.

The company projected diminishing costs and said its capital spending would fall by 30%.

Energydesk has approached Shell, Transocean and Noble Corp for comment, but not received responses.

A Shell spokesperson told the Guardian on safety: “We’ve said clearly that our plans must meet our own high bar as well as the one set by US regulators. Both have taken unprecedented measures to ensure offshore operations and contingency plans in the US Arctic are second to none.”